MONOGRAPH 



THE FRESH-WATER POLYZOA, 



INCLUDING 



ALL THE KNOWN SPECIES, 



BOTH BRITISH AND FOREIGN. 



BY 



GEOUGE JAMES ALLMAN, M.D., E.R.C.S.I., E.R.S., F.R.S.E., M.E.I.A., 



REGIUS PROFESSOR OF NATURAL H15T0RV IN THE UNIVERSITY OF EDINBURGH. 



LONDON: 



PRINTED FOR THE RAY SOCIETY. 



